Wilson's New XLF Flagship Loudspeaker: A World Exclusive Preview

Wilson Audio invited me to Provo, Utah just a few days before Christmas for an early look and listen to its new top-of-the-line Alexandria XLF loudspeaker. TAS Contributing Writer Jacob Heilbrunn, who owns Wilson's X-2 Series 2 loudspeakers, met me there for the factory tour and audition. Interestingly, the $195,000 Alexandria XLF doesn’t replace the $168,000 Alexandria X-2 Series 2 but rather extends the Alexandria line with a higher-end model.

Before listening to the XLF we visited the Wilson factory to see the new flagship in production and to tour the factory expansions and upgrades since my last visit three years ago. Despite having toured the factory twice before, I was struck by the extraordinary level of craftsmanship that goes into every production step. It's really quite an amazing operation.

Visually, the XLF looks very much like an X-2; the technology advances are not readily apparent at a glance. The XLF is based on the same modular platform as the X-2, but incorporates a new Wilson-developed tweeter along with different bass loading, a 14% increase in bass-enclosure volume, crossover changes, and a unique “Cross Load Firing” port that gives the loudspeaker its name. This feature allows the installer to choose front or rear venting of the port by installing a 12-pound port "plug" in either the front or rear baffle. The ability to select a front- or rear-firing port enables the XLF to produce better bass performance in a wider range of listening rooms and of positionings within those rooms. Wilson has applied for a patent on the Cross Load Firing technology. The bass enclosure has also been strengthened with thicker X-material and improved internal bracing. In addition, the "wings" that support the midrange and tweeter modules have been thickened, and their internal surfaces damped. The wider wings cover more of the modules, giving the XLF a more streamlined look compared with the X-2.

After the factory tour we visited Dave Wilson's home where he showed us a sampling of the wide range of tweeter technologies he considered for the XLF (including diamond, ceramic, and beryllium diaphragms), commenting on the strengths and shortcomings of each. He noted that price was not an issue, and that he was not biased by any of the current trends in tweeter diaphragm materials. Rather, he chose the technology that best worked musically for the XLF. After three years of research, he decided upon a silk dome tweeter. This is an unusual step to say the least; soft-fabric domes were popular in the 1980s but have largely given way to high-tech materials that are light and stiff. Nonetheless, Wilson emphasized that the loudspeaker’s musical performance, along with the totality of the design, trumps adherence to the latest trends. The company addresses this issue head-on in the XLF press release: “The new Wilson tweeter rejects exotic materials in favor of a new silk dome that better meets all of Dave’s musical design goals.” Wilson calls this driver the “Convergent Synergy” tweeter, which reportedly goes low enough in frequency to blend with the Wilson midrange driver, has wide dispersion, high-power handling, wide bandwidth, and ruggedness in the field. Note that the new tweeter is not a drop-in replacement for the tweeters in current Wilson loudspeakers. Moreover, there are no immediate plans to integrate the silk dome into other speakers in the line; the tweeter was developed specifically for the XLF.

After the tweeter discussion we went into the listening room to audition the XLF and compare it with the X-2 Series 2. Dave's home features an enormous custom-designed listening room with superb acoustics. Walking in, we saw the X-2 Series 2 and the XLF side-by-side, connected with a switcher that allowed the listener to select between the speakers. We listened to a number of musical selections that had been chosen to best reveal the differences between the X-2 Series 2 and the XLF, followed by listening to just the XLF without the switcher in the signal path.

When I heard an identical setup comparing the X-2 Series 1 with the X-2 Series 2 three years ago, the Series 2 was dramatically better sounding in the midrange—more open and detailed, with far greater clarity and resolution. Although the successor model exhibited other refinements, it was the midrange improvement that defined the Series 2. But the difference between the X-2 Series 2 and the new flagship XLF was more nuanced. Rather than exhibiting a large advance in a single area, the XLF benefited from a whole host of more subtle enhancements that, collectively, resulted in a significant upgrade over the X-2.

First, the XLF had tighter image focus and precision in delineating image outlines. Centrally placed voices were more compact in the middle of the soundstage, yet this smaller image size did not come at the expense of overall soundstage width. Large-scale music was rendered with the same sweeping scale, but with greater spatial precision of individual instruments within the stage. Moreover, the XLF's portrayal of image size changed more dramatically with the size of the instrument or section of instruments; smaller instruments sounded smaller, just as they do in life. In an interesting demonstration, I compared the image size of an actual 6’ Yamaha grand piano in the listening room, the Series 2, and the XLF. The actual piano played, via a Disk Clavier, a piece of music while I listened at the same distance as the microphone placement of the Wilson-made recording we were about to hear. We then heard that same piece of music (same pianist but a different piano in a different venue) on the X-2 Series 2 and then the XLF to compare the two loudspeakers' respective image sizes relative to that of the actual piano. The XLF produced a spatial perspective more like that of the live piano, making the X-2 Series 2 sound a bit diffuse and billowy by comparison. In subsequent listening, the XLF's tighter focus produced a more believable and palpable rendering of instruments and voices.

The XLF's tonal balance was very similar to that of the Series 2, but with somewhat less upper-bass energy and a bit more life and verve in the upper-midrange and treble. The Series 2 was a little "thick"-sounding by comparison, with a darker and heavier rendering. The XLF's reproduction of instrumental harmonics was more lifelike, both because of the somewhat more "illuminated from within" quality but also from the smoother textures and greater resolution. The Series 2's treble had a slight edge and hardness, particularly on transients, that was lacking in the XLF. The XLF's midrange and treble were better integrated, and the increased refinement, clarity, and reduction in treble grain gave the sound a cleaner and more coherent quality. The increased midrange resolution, coupled with the greater image focus, presented a more palpable impression of a tangible instrument or voice surrounded by the acoustic. The decay of sound in the recording venue was more finely textured and nuanced through the XLF, and was resolvable to lower levels. The XLF had a superior ability to reach down into lowest level details and finest reverberation decays.

Transient performance was also improved. In addition to the lack of hardness on transient leading edges, the system seemed to settle down more quickly and deeply. Intricate dynamic passages were more coherent and defined, without a sense of blur or smear. This was true over the entire frequency range, from the midbass through the treble. The XLF sounded "lighter on its feet" and more agile dynamically.

Finally, we listened to the XLF with no switcher and with a pair of Wilson's Thor's Hammer subwoofers augmenting the bottom end. This was an absolutely stunning system in every possible way.

Given the overall sonic superiority this new flagship has over the X-2 Series 2, along with the relatively modest price differential, I’d be surprised if the X-2 remains in the line. The XLF begins shipping in January. I’m scheduled to get a pair for a full review.